Question

Find kinctic energy of 4000 cc of a gas at S.T.P.

[Given: Standard pressure is 1.013 × 10⁵ N/m²]

Answer 1

Given:

Volume of gas, V = 4000 cc = 4000 × 10⁻⁶ m³

Standard pressure, P = 1.013 × 105 N/m²

Standard temperature, T = 273 K

Universal gas constant, R = 8.314 J/mol·K

Formula:

Using Ideal Gas Equation to Find Number of Moles (n) 

PV = nRT

`n = (PV)/(RT)`

n = `((1.013 xx 10^5) xx (4000 xx 10^-6))/(8.314 xx 273)`

n = `405.2/2269.662`

n ≈ 0.1786

The total kinetic energy of an ideal gas is given by:

K.E. = `3/2 nRT`

K.E. = `3/2 xx 0.1786 xx 8.314 xx 273`

K.E. = `3/2 xx 405.2`

K.E. = 607.8 J